The principal data products from the 915 MHz Met Office boundary-layer wind-profiler are the wind speed and (meteorological convention) direction, as functions of time and altitude; radial velocities and signal-to-noise ratios (S/Ns) for individual beam directions are also given. Observations are made in both a "low" mode, covering the approximate altitude range 0.1 - 2.0 km at 0.1 km intervals, and a "high" mode, covering the approximate altitude range 0.2 - 8.0 km at 0.2 km intervals; the useful coverage varies with atmospheric conditions.
Each file begins with a blank line and is then followed by a sequence of 96 records; 48 for the low mode and 48 for the high mode. NOTE that the order of low and high mode records is not necessarily the same for each 30 minute period; it is therefore necessary to determine the mode from the inter-pulse-period, IPP, in header line 7 described below. The first 15 lines of the first record in ukmo-radar-1290mhz-2_wattisham_20021231.txt are shown as follows exactly as they appear in the file:
Wattisham Airfield WINDS rev 4.1 52.10 1.00 87 02 12 31 00 00 00 0 30 3 19 06:08 (2.5) 06:08 (2.5) 06:08 (2.5) 144 144 127 127 700 700 23 23 17.5 17.5 1 2100 2100 19 19 700 700 133 90.0 133 74.5 43 74.5 HT SPD DIR Radials... 0.152 9999 999 0.3 0.6 12.1 8 8 5 4 5 -8 0.253 11.0 48 0.8 1.0 3.7 8 8 8 9 13 6 0.354 10.7 52 0.8 1.2 3.6 8 8 8 9 11 9 0.455 11.2 53 0.9 1.4 3.9 8 8 8 4 8 7 0.556 10.8 47 0.5 0.6 3.3 8 8 6 3 6 6
For most purposes the only header information that is actually required consists of the date and time of observation from line 4, the number of altitude gates, NAG, from line 5 (each record consists of NAG+11 lines), and the pulse length from line 7. In the explanations of the line contents below, some of the horizontal spacings have been altered for the sake of clarity. The text shown in red is for descriptive purposes only and does not appear in the files.
Lines 1 - 3 give the station name, the file format and station position, respectively; they are the same in all records.
Wattisham Airfield
WINDS rev 4.1
52.10 1.00 87
LAT LONG ELEV
Line 4 gives the date and time at the start of the consensus period.
01 09 03 00 00 18 0 YY MM DD hh mm ss UTOFF
Line 5 gives observational format details.
30 3 19 CAP NBD NAG
Line 6 gives consensus details for each beam direction used; the beam directions are given in line 9.
06:08 (2.5) 06:08 (2.5) 06:08 (2.5) NCRC:NCT CWS NCRC:NCT CWS NCRC:NCT CWS
Line 7 gives observation format details. Two values are given for each parameter; the first relates to the off-vertical beam observations and the second to vertical beam observations.
144 144 127 127 700 700 23 23 NCC NCC NSP NSP PLEN PLEN IPP IPP
Line 8 gives more observation format details; again the first of each value corresponds to off-vertical beam observations and the second to vertical beam observations.
17.5 17.5 1 2100 2100 19 19 700 700 MDV MDV VC TDFG TDFG NRG NRG RGI RGI
Line 9 gives the beam pointing directions.
133 90.0 133 74.5 43 74.5 AZIA ELEA AZIA ELEA AZIA ELEA
Line 10 gives labels for the columns that follow
HT SPD DIR Radials...
Lines 11 to (10 + NAG), of which only the first 5 are shown, give the actual data. Radial data (columns 4 to 12) are given in the beam order defined in line 9.
0.152 9999 999 0.3 0.6 12.1 8 8 5 4 5 -8
0.253 11.0 48 0.8 1.0 3.7 8 8 8 9 13 6
0.354 10.7 52 0.8 1.2 3.6 8 8 8 9 11 9
0.455 11.2 53 0.9 1.4 3.9 8 8 8 4 8 7
0.556 10.8 47 0.5 0.6 3.3 8 8 6 3 6 6
Z SPD DIR VRAD VRAD VRAD NCMC NCMC NCMC S/N S/N S/N
Line (11 + NAG) contains a single $ character.
Return to main Wind Profiler page.
Thanks to David Hooper, RAL for this page.